1. Field of the Invention
The present invention relates to a method of patterning a nano conductive film. More particularly, the present invention relates a method of patterning that can be performed under milder conditions than deposition without affecting the thermal stability of the resulting device.
2. Description of the Related Art
Devices with higher integration and precision are required as the semiconductor industry progresses, and thus, micromachining techniques for embodying smaller and more precise micro patterns are required.
Accordingly, there is a need for simple and highly precise patterning of nano conductive particles.
Patterning nano conductive particles using wet process is not performed conventionally. It is almost impossible to disperse nano conductive particles using only wet processing due to properties of nano conductive particles, and thus, in order to disperse nano conductive particles uniformly, a binder such as a polymer was used. That is, generally, a binder polymer is dissolved in a solvent, and nano conductive particles are dispersed therein, and then the mixture is uniformly applied to a surface for patterning. However, such a method results in the deterioration of the conductivity of the nano conductive particles due to the lack of electric conductivity of a polymer.
Further, patterning of indium tin oxide or indium zinc oxide which is widely used in display devices is conventionally achieved by deposition. This method has problems in that it is a high energy-consuming process requiring a high temperature, a required shadow mask is expensive, and deformation occurs due to the expansion of the shadow mask caused by radiant heat, thereby limiting patterning precision.
Furthermore, mobile display devices with paper-like flexibility and high display quality are being developed. In such a flexible display, in order to obtain true flexibility and light weight at low costs, a glass substrate must be substituted with a transparent and flexible plastic substrate. However, a plastic substrate has very low heat-resistance compared to a glass substrate, and can only handle temperatures of about 150° C. to 200° C. Accordingly, deposition on a plastic substrate is limited.
Thus there is a need for a method of patterning a uniform film by dispersing nano conductive particles using a wet process.